The present invention relates to a method and an apparatus for machining workpieces, in particular for metal cutting machining of metallic workpieces. More particularly, the invention relates to a method and an apparatus using a novel approach for efficiently distributing cutting tools to storage places of a tool magazine during machining operations.
German patent publication DE 43 11 469 C1, which is assigned to the present assignee, discloses a machine tool having a tool magazine which is designed as a chain magazine having a revolving chain. Storage places for the cutting tools are arranged on the chain. A cutting tool is picked up and deposited at a defined peripheral position of the chain. Arranged at another peripheral position is a gripper which is capable of removing a cutting tool from a storage place and depositing it in a storage place. During operation of the machine tool, in each case that storage place which lies directly adjacent to a storage place having the next tool in the sequence of the cutting tools is cleared by means of the gripper. In this way, the tool change can be carried out very rapidly, because the previous cutting tool is deposited directly next to the subsequent cutting tool.
The method and the apparatus from DE 43 11 469 C1 have proved successful in practice. They permit a rapid tool change and short chip-to-chip times, because the clearing of the adjacent storage place of the following tool is effected at the same time as the machining of the workpiece with the previous tool. In addition, the known apparatus is of simple and cost-effective construction, and it offers the user the possibility of loading the tool magazine “chaotically”, i.e. the user need not match the loading of the tool magazine to the sequence during the machining of the workpiece.
However, it has been found in the practical application of this known method and apparatus that the cutting tools in the tool magazine have to be rearranged relatively frequently, which may lead to increased wear of the revolving chain and of the individual holders for the cutting tools.